I have a copy of Weidenreich's book, "Apes, Giants, and Man" which was written in 1946. This book has some very interesting pictures of the Paleojavanicus fossil jaw, most notibly the Sangiran 6. mandible. The structure of this Erectine certainly suggests a sort of genetic gigantism was present.
I do not know of any other Meganthropus findings, but have heard that there were some fossils of it found in Africa.
Weidenreich does not outright tell us how tall Meganthropus was in his book, but indicates a massive weight of 600 or more lbs. "twice the size of a Gorilla" he said.
All in all, It doesn't look like many Meganthropus specimens have been found or well published. If a giant of this sort has been confirmed I would think the scientific community would show as much interest or even more so than homo floresiensis. However, from reading archive News articles from the late 40's, Meganthropus did get some spotlight in the NY Times and Washington Post with headlines such as "Largest’ Ape Man Found in Africa; Indicated to Top 9-Foot Java Man" NYTimes[Dec 1, 1948]
™ Version 4.2